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A Method To Disperse Aggregates of a Flocculent Yeast for Photometric Analysis
Author(s) -
CastellonVogel Martha A.,
Menawat Anil S.
Publication year - 1990
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp00002a007
Subject(s) - flocculation , dilution , yeast , absorbance , settling , sodium , chemistry , chromatography , suspension (topology) , saccharomyces cerevisiae , optical density , biochemistry , environmental engineering , environmental science , organic chemistry , optics , thermodynamics , physics , mathematics , homotopy , pure mathematics
Abstract Strategies to disperse aggregates so the cells remain in suspension long enough to take stable absorbance readings are studied. The optical density of highly flocculating yeasts, such as Saccharomyces cerevisiae ATCC 26603, drops because of cells settling to the bottom in less than 1 min. It presents a problem in using turbidimetric measurement for cell density estimate. Dilution of the yeast samples with sodium salts in a wide range of concentrations (10 mM to 1 M) disperses the aggregates, whereas dilution with calcium salts does not. ζ‐Potential measurements indicate that sodium disperses the yeast flocs by reversal of the charges on the cell surfaces. An attempt is also made to resolve the controversy about the role of sodium ions in flocculation.